This was a point I ALWAYS questioned. The bible - even their NWT included the Holy Spirit, yet the organization can do away with it as they see fit.
" But the helper, the holy spirit, which the Father will send in my name, that one will teach you all things and bring back to your minds all the things I told you." (John 14:26)
This tells me that the Spirit will direct the education of the faithful, not a worldly organization who vote doctrine in and out of their faith when it pleases them.
And I always thought the memorial was pointless - we aren't invited to rejoice with Christ? We're not welcome at his table? How can that be?